PTL 1 discloses an adapter configured to couple a set of ear pieces and a microphone to a cellular phone. The adapter includes a mute switch and a talk switch. A user can operate the mute switch of the adapter to turn off the microphone, as well as can operate the talk switch to achieve communications.
For communication devices to be coupled to headsets, a half-duplex communication method typically applied in transceivers and a full-duplex communication method typically applied in cellular phones and smartphones are available. Further, transceivers can be divided into two kinds of transceivers different from each other in wiring configured to detect that a PTT switch is pressed. Microphones to be coupled to headsets can also be divided into two kinds of microphones, i.e., bone conduction microphones each equipped with a PTT switch and ordinary sound microphones each not equipped with a PTT switch.